In general, the present invention relates to a door tensioning device or tensioner. Such devices are commonly used to maintain and adjust the tension of a spring used to counterbalance the weight of an upwardly opening door. One type of upward opening door is a rolling door, which uses a curtain made of flexible material or a plurality of panels that is coiled up around itself as the door is opened. One end of the curtain is attached to steel wheels that are welded or otherwise affixed to a support axle. This support axle, often referred to as a live axle because it rotates as the door is opened, is supported and journaled at its ends by brackets attached to the header or jambs of the door. To provide a counterbalancing force for the weight of the door, a spring is attached at one end to one or more of the wheels and at its other end to a tensioning assembly. In the past, the door""s support bracket would act as the tensioning assembly. In this instance, the door typically would arrive at the place of installation in its open position i.e., the curtain being completely coiled around the axle. Once the curtain and axle were mounted on the support brackets, the free end of the spring would be attached to one support bracket and the door would be rotated through one or more rotations to charge the spring. At this point, a bottom bar of the door would be inserted into vertical guides to prevent the door from rotating. Optimally, the counterbalance spring would have sufficient tension such that the door would fully close and only a small amount of force would be necessary to raise the door from the closed position. If the door is not in the optimal position, the installer would adjust the spring tension by removing the bottom bar from the guides and repositioning the end of the spring and the support bracket. After which, the installer would reassemble these components and repeat the pre-tensioning procedure to charge the spring.
To avoid repositioning of the spring on the bracket, alternative tensioning assemblies have been developed. In one such assembly, an axle tube is provided with a spring attaching plate and a tensioning plate. The tube is fitted over the axle such that these plates may move independently of the axle. The plates are located on either side of the tensioning bracket and an end of the counterbalance spring passes through the spring attaching plate to eventually attach to the bracket. With the spring so attached, the axle tube may be rotated to increase or decrease tension on the spring. All of the plates are provided with a plurality of holes located radially equidistant from the center of the axle. To maintain the tension on the spring, a pin is passed through the holes in each plate to fix the plates relative to each other and the bracket preventing rotation of the axle tube. Adjustment may be made by removing the pin and rotating the axle tube toward the next appropriate hole.
As will be appreciated, this tensioning assembly may be difficult to use. The user must rotate the axle tube with a suitable tool in one hand to align the holes in the spring attaching plate, tensioning bracket, and tension plate, and with the other hand attempt to insert a pin through these holes while maintaining the alignment. As a result, once the installer has the holes aligned, he must maintain the exact tension on the axle tube to preclude relative rotation while inserting the pin.
A further disadvantage of this system is that the slidable pin may become disengaged by efforts to tamper with the door or other accidental contact with the pin. Essentially, the pin is not axially held, but for the frictional forces created by the plates and bracket. Therefore, a person could possibly remove the pin without tools or extensive effort causing unintentional release of the spring""s tension. It will be appreciated that such a release could make it difficult or impossible to operate the door and, in more dire instances, cause serious injury.
It is, therefore, an aspect of the present invention to provide a door tensioner that automatically prevents rotation of the axle tube as the installer rotates the tube to a desired position. A further aspect of the present invention is to provide a tensioning assembly that includes a gear and spring-loaded pawl to hold the axle tube at the desired position.
It is another aspect of the present invention to provide a locking assembly that locks either of the gear or pawl to the support bracket, where the locking assembly cannot be removed without extensive effort or the aid of tools. It is a further aspect of the present invention to provide a fastener supported on the pawl that may be driven into the support bracket to lock the tensioner in place.
The present invention generally provides a tensioner in a rolling door system, the rolling door system having a door attached to at least one wheel supported on an axle, the axle being rotatably supported on a pair of support brackets, the support brackets each defining a bore through which the axle is received and a counterbalance assembly that generates a counterbalancing force, the counterbalance assembly having a first end attached to the tensioner and a second end attached to the axle, the tensioner including a sleeve that fits over an end of the axle and is rotatably supported in the bore of the support bracket; a spring holder and a gear wheel attached to the sleeve, wherein the second end of the counterbalance assembly attaches to the spring holder; the gear having a plurality of teeth defining a plurality of notches therebetween; a pawl movable between a disengaged position and an engaged position, the pawl retaining the gear in a position when in the engaged position; the pawl being biased toward the engaged position, whereby the pawl automatically engages the gear to retain the counterbalancing force generated by the counterbalance assembly to balance the weight of the door.
The present invention further provides a rolling door including an axle supported by end brackets, a plurality of drum wheels mounted on the axle, a multi-section door adapted to be selectively rolled and unrolled about the drum wheels, a gear wheel mounted on the axle proximate to one of the end brackets, a spring retainer associated with the gear wheel, a torsion spring having a first end operatively attached to the multi-section door and a second end attached to the spring retainer, a pivotally mounted pawl selectively engaging the gear wheel to maintain a selected counterbalance force setting and disengaging the gear wheel to permit adjustment of the counterbalance force setting, and a locking assembly carried on the pawl selectively engageable with the support bracket to lock the pawl in an engaged position.
A rolling door including, an axle supported by end brackets, a plurality of drum wheels mounted on the axle, a multi-section door adapted to be selectively rolled and unrolled about the drum wheels, a sleeve rotatable on the axle, a gear wheel attached to the sleeve, a spring retainer associated with the gear wheel, a torsion spring having a first end attached to the multi-section door and a second end attached to the spring retainer, a pivotally mounted pawl selectively engaging the gear wheel to maintain a selected counterbalance force setting and disengaging the gear wheel to permit adjustment of the counterbalance force setting, and a locking assembly carried on the pawl selectively engageable with the support bracket to lock the pawl in an engaged position.
The present invention further provides a rolling door assembly including an axle supported by end brackets, a plurality of drum wheels mounted on the axle, and a multi-section door adapted to be selectively rolled and unrolled about the drum wheels, a tensioner associated with the axle, a torsion spring having a first end operatively attached to the multi-section door and a second end operatively attached to the tensioner, the tensioner including a gear wheel having a plurality of teeth, the teeth having an undercut stop face, and a pivotally mounted pawl selectively engaging the stop face to maintain a selected counterbalance force setting.